Powertech Transformers, a subsidiary of Powertech and the JSE listed Altron Group, announced that they have recently installed in their Pretoria laboratory state-of-the-art Brockhaus equipment which is used for testing of core steel making it the only company in Africa with this type of equipment and only a few companies in the world.

The equipment includes the following:
• An Epstein Frame
The purpose of the instrument is to measure the properties of ferromagnetic material and was developed for transformers and motors. It can measure field strength and hence the losses of the core material.  Although this type of instrument employs old technology, it has proven reliability and effectiveness – many international standards refer to the Epstein test - IEC 60404-11, ASTM A717-93 and JIS C 2550.  The disadvantage of this unit is that one cannot test the internal stresses of the material due to bending or flipping or handling, that lead to higher losses during testing.
• Single Sheet Sensor Tester 250x250mm
In addition to the Epstein Frame Tester, this unit measures the material properties. It produces the loss measurement of the material. This instrument can measure internal stress of the material due to handling. The results can be converted to Epstein Frame results, but vice versa is not possible. This is the latest technology in core steel measurement, but many standards still enforce Epstein Frame Test results.
• Stacking Factor Tester
Measurements are performed with the stacking factor tester in accordance with IEC 60404-13 to determine the “filling factor” of the core steel packet space factor. The ratio of core material to other material, e.g. oil, pressboard and particles in the close proximity of the core is determined.
• Franklin Tester
The Franklin Tester for surface resistance is used to determine the quality aspects of soft magnetic materials.
• Measure surface resistance
• Resistance distribution
• The thickness of the coating on electrical steel and punched parts (in extreme cases).
The advantages of accurate Core Steel property measurements are as follows:
• When test results, e.g. loss measurements on core material certificates arrive from suppliers, we are able to verify the accuracy thereof. Early detection of major loss fluctuations in the no-load losses
• Calculation and manufacturing of the core to such an extent as to achieve the optimal filling factor
• Ability of measuring the insulation resistance during manufacturing and decreasing  loss deviations based on material handling.

The manufacturer of the equipment, BROCKHAUS MESSTECHNIK, has many years of experience and well-proven expertise in the field of testing electrotechnical materials.  They are the leading manufacturer in Europe of measuring systems for quality control of magnetic materials. Bernard Meyer, CEO Powertech Transformers says “Incoming material control and verification of supplier routine test results for critical material items such as electrical core steel is of utmost importance to PTT as this drives customer confidence as a reputable OEM of power transformers. No-load losses are important guaranteed design and manufacturing parameters in terms of contractual compliance, and therefore necessitates us to have full control of our Supply Chain for electrical core steel.” PTT supplies a full range of transformers, from generator step-up to transmission and distribution transformers. The range includes three-phase and single-phase units, auto-transformers, arc-furnace, locomotive and traction transformers, miniature sub-stations, NECRT’s as well as and shunt reactors.